Merge pull request #7 from malini/scrollfps

Remove arbitrary sleeps, fire stop_fps when touchend is fired
Remove sleep after launch, as there is already a suitable wait in the launch method
PEP8 fixes
Use wifi details from testvars for FPS scrolling tests if provided
Use progressbar for FPS scrolling tests
Allow FPS test for email app to fail if there are no emails visible
Fix exception message when element is not visible
Print full stack traces on exception
Introduce restart b2g process and settle time to FPS tests
Improved exception messages
Removed unused variable
Implemented a basic wait class and improved waits for all FPS tests
race condition fix and sanity restoration